The board setup shows squares of three colours on a 5x5 board. Around the center square there are two coloured rings. All squares in these rings move one step at a time.
To achieve this, you can either move one square in these rings or click one of the round arrows at the bottom.
Also, the middle row and column of squares can be shifted.

To start playing, click the board to randomize the position.
You win if you can recreate the original position.

Variants : more complicated setups (and more difficult to solve).

Please note that there is an alternative piece set available.